1. Field of the Invention
This invention relates to an electrophotographic photosensitive member, a process cartridge and an electrophotographic apparatus. More particularly, it relates to an electrophotographic photosensitive member having on a conductive support at least a charge generation layer, a charge transport layer and a protective layer in this order, and a process cartridge and an electrophotographic apparatus which have such an electrophotographic photosensitive member.
2. Related Background Art
In recent years, electrophotographic photosensitive members are required to be made further durable. For example, Japanese Patent Application Laid-open No. 5-173350 discloses that an electrophotographic photosensitive member having very good durability can be provided by forming on a photosensitive layer a protective layer which contains a curable resin. As another example, Japanese Patent Application Laid-open No. 7-5748 discloses what is called injection charging, in which electric charges are injected into a protective layer on a photosensitive layer without being accompanied with any substantial discharge.
However, while an electrophotographic photosensitive member having a protective layer has the above-mentioned advantages, positive ghosts or negative ghosts are liable to occur. In addition, such phenomena become conspicuous particularly in a case where the protective layer contains a curable resin as a binder resin.
On the other hand, with the recent development of full-color photography or the minuteness realized by dots as small as 1,200 dpi (dot per inch), much higher image quality is demanded.
An object of the present invention is to provide an electrophotographic photosensitive member which hardly causes positive ghosts or negative ghosts even in repeated use and can stably provide high grade images.
In addition, other objects of the present invention are to provide a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member.
That is, the present invention provides an electrophotographic photosensitive member comprising, in this order, a photosensitive layer and a protective layer on a conductive substrate, wherein the surface of the electrophotographic photosensitive member is charged to xe2x88x92700 V and irradiated with white light in a light quantity of 10 luxxc2x7sec under a 23xc2x0 C./5% RH environment, where Vsl(0.2), which is a surface potential of the electrophotographic photosensitive member at the time 0.2 seconds have passed from the irradiation, satisfies the following formula (1) and the difference between the Vsl(0.2) and Vsl(0.5), which is a surface potential of the electrophotographic photosensitive member at the time 0.5 seconds have passed from the irradiation, satisfies the following formula (2):
20(V)xe2x89xa6|Vsl(0.2)|xe2x89xa680(V)xe2x80x83xe2x80x83(1)
10(V)xe2x89xa6|Vsl(0.2)xe2x88x92Vsl(0.5)|xe2x89xa630(V)xe2x80x83xe2x80x83(2).
The present invention further provides a process cartridge and an electrophotographic apparatus having the above electrophotographic photosensitive member.